Free-energy change, ?G?, is related to cell potential, E?, by the equation ?G?=?nFE? where n is the number of moles of electrons transferred and F=96,500C/(mol e?) is the Faraday constant. When E? is measured in volts, ?G? must be in joules since 1 J=1 C?V. Calculate the standard cell potential at 25 ?C for the reaction X(s)+2Y+(aq)?X2+(aq)+2Y(s) where ?H? = -651kJ and ?S? = -371J/K.